.con{
    width: 800px;
    height: 400px;
    background: snow;
    opacity: 0.8;
    margin: 0 auto;
    border: 1px solid snow;
    border-radius: 10px;
}
.main_con{
    width: 700px;
    height: 100%;
    margin: 0 auto;
}
.title{
    text-align: center;
    font-family: 华文行楷, serif;
    font-size: 50px;
    text-align: center;
    margin: 0;
}
.intro{
    font-family: "微软雅黑", serif;
}
.bt{
    width: 180px;
    height: 40px;
    margin: 0 auto;
}
.btn-danger{
    border-radius: 5px;
}
.btn-danger:hover{
    cursor: pointer;
}